Electric switch



Nov. 17, 1942. C, A, SCHAEFER 2,302,582

ELECTRIC swITcH l Filed Aug. 14, 1939 3 Sheets-Sheet 1 Nov. 17, 1942. c. A. scHAr-:FER

ELECTRIC SWITCH Filed Aug. 14, 1959 5 Sheets-Sheet 2 l ATTORNEY Nov. 17, 1942.

C. A. SCHAEFER ELECTRIC SWITCH Filed Aug. 14, 1939 3 Sheets-Sheet 3 ,Ll 'N /N VENTOR fr] H c'defenr BY v A TTORNEY Patented Nov. 17, 1942 sA PATENT OFFICE i ELECTRIC swrrcn Carl A.'Schaefer, Whitefish Bay,'Wis., assignor to Square D Company, Detroit, Mich., a corporation of Michigan Application August 14, 1939, Serial No. 290,032

(CI. ZIN-83) 19 Claims.

This invention relates to electric switches and more particularly to switches automatically operable in response to a external condition.

An object of the present invention is to provide an improved form of electric switch operating with a snap action in response to an external condition.

Another object of the present invention is to provide an improved electric switch in which the contacts are provided with a relatively large sliding movement to supply a material wipe thereto before being moved to disengaged position.

Another object of the present invention is to provide means carried by the main operating lever adapted to engage and move the contact lever if the contacts should weld 'to break said weld and restore the switch to normal operation.

Another object of the present invention is t provide an improved snap acting electric switch in which the contact pressure is of a substantial value until the contacts are 'sharply snapped to disengaged position.

Other objects and features of the invention will be readily apparent to those skilled in the art from the following specifications and appended drawings illustrating certain preferred embodiments of the present invention.

Figure 1 is a perspective view of an electric switch according to the present invention.

Figure 2 is a horizontal sectional View taken on the line II--II of Figure 1.

Figure 3 is a horizontal sectional view taken on the line III-III of Figure 1.

Figure 4 is a sectional view taken on the line IV-IV of Figure 2.

Figure 5 is a view similar to Figure 4 but showing the parts in "on position.

Figure 6 is a sectional view taken on the line VI-VI of Figure 2.

Figure 7 is a vertical sectional view taken on the line VII--VII of Figure 4.

Figure 8 is a vertical sectional view taken on the line VIII-VIII of Figure 4. K

Figure 9 is a vertical sectional view taken on the line IX--IX of Figure 4.

The switch as illustrated in the drawings comprises a housing I formed of a single metal strip bent into a generally U-shape, having legs 5 and 6 with fianges 4 thereon to which a bridging member 3 is rigidly secured as by welding. The housing I is provided with a normal pressure responsive actuating means 9 and a means responsive to a predetermined maximum pressure II.

Said housing I is also providedwith openings 1 therethrough for the passage of lead in wires, and carries a closure piece 8 interchangeably receivable by said openings 1. Disposed within the housing I and secured to the underside of bridging member 3 as by studs i2 and I3 is an insulated contact block I4 upon which are securely mounted as by studs the U-shaped contact elements I5. The upper legs I6 of said contact elements I5 are adapted to carry terminal` studs Il for securing cable terminal ends thereto and the lower legs I8 serve as stationary contacts.

Transversely spaced bent up portions I9 are provided by base 2| of housing I and carry a pin member 22 whereby a generally U-shaped in cross section main operating lever 23 is pivotally supported. Two oppositely directed pairs of knife edge seats 24 and 25 are carried by said main operating lever 23 adjacent its upper edge.4 A freely swingable link or lever 26 carrying knife ledge pivots 2l upon either side and near its left extremity (as viewed in Figure 1) is pivotally supported within the knife edge seats 25. A contact lever 28 carrying knife edge pivots 29 upon either side and at the approximate midpoints thereof is pivotally mounted'within the knife edge seats 24. An insulating plate 3| is secured at the left hand end of said contact lever 28 and carries contacts 32 thereon for cooperation with the stationary contacts I8 to complete a circuit therethrough. A counterweight 33 is secured to the left hand end of the swingable lever 26.

A pair of springs 34 interconnect the freely swingable link 26 and the contact lever 28 and bias their knife edge pivots 2l and 28 into their respective seats 25 and 24. A generally L-shaped member 35 is rigidly secured to side 6 of the housing I and carries a pair of inwardly extendly arms 36 disposed above and below the swingable link 26 and thus serve as stops limiting the upper and lower positions of said freely swingable link 26. An adjustable stop pin 31 is carried by the base 2l and is located intermediate the knife edge seat 25 and the point `of attachment of the spring 34 to the rightv hand end of the freely swingable link 26 and serves a purpose to be hereinafter described.

A range spring 38 is disposed between a spring seat formed upon the main operating lever 23 and a movable spring seat 39 threadingly carried by a stud 4I and exerts its bias to oppose the upwardly exerted force of the pressure responsive actuating element 9. The head of said stud 4I extends through an opening in the bridging member 3 and is provided with a cross-slot whereby it may cooperate with a screw driver to rotate said stud 4I and move the movable spring seat 39 to thereby change the pressure setting. A collar member 42 is rigidly secured to said stud 4I adjacent the head thereof and is brought to bear against the under surface of the bridging rnember 3 by the bias of the range spring 38, thus providing a means for holding said stud 4I in position.

Means for changing the differential at which the switch operates in moving to on and to off positions is provided by a stud `43 threaded into a spring holding nut 44 which carries the upper extremity of a diierentlal tension spring 45. Also, adjustably mounted upon the stud 43 are nuts 46 and 41. A slidable link member 48 carries the lower extremityof the differential spring 45 and has a projecting portion upon its upper extremity extending into the stop nut 46, with shoulder portions engageable y the lower rim of said nut 46 when said link is moved upwardly to thereby limit the upward movement. A ridge like portion 49 is formed upon the base 2i, with an opening therethrough to receive the lower extremity of said slidable link 48, positioning said link. A projection 5i carried at the left hand end of the main operating lever 23 is received by an opening in the slidable link 48 providing thereby a lost motion connection between said main operating lever 23 and said-slidable link 48. Through this lost motion connection said slidable link 48 is adapted to be picked up by the -main operating lever 23 when the latter is moved in a counter clockwise direction under the action of the pressure responsive actuating means 9 to thus add the bias of the tension spring 45 to that of the rangeA spring 38. .In the return, clockwise, movement of the operating lever upon vals the lessening of pressure, the link 48 engages the stop nut 46 to release the 'bias of said tension spring 45 upon said main operating lever 23. The third nut 41 carried by stud l43 is disposed above the stop nut 46 and serves to lock the latter in any desired position. The head of the differential stud 43 extends through an opening in the bridging member 3 and is provided with across slot for cooperation with a screw driver whereby the spring holding nut 44 may be moved to adjust the tension of the differential spring 45. A plate like member 52 is disposed between the heads of studs i2 and 43 and is adapted .to bear thereagainst to maintain the diiferential stud 43 in its proper position; the stud I3 rigidly secures said plate in place.

To assist in obtaining the proper setting of the differential spring 45 and the range spring. 38, Ithe bridging member 3 provides downwardly extending iiange indicia bearing portions 53 and 54 disposed between said differential and said range spring.

rlhe normal pressure responsive element 8 includes an exterior casing 5'5. Within the casing 55 is disposed a corrugated bellows portion 56 having an actuating pin 51 connected thereto and extending into the switch housing l, a bear- -ing point 58 is provided upon the end of the `actuating pin 51 and is received Within a corresponding impression in the main lever 23 to move the latter when it itself is moved.

The operation of the switch will now be described.

With a rise in pressure to a predetermined amount, the actuating pin 51 will be forced upward causing the main opera-ting lever 23 to rotate in a Acounter-clockwise direction. This movement of main operating lever 23 causes the knife edge seats 24 and 25 to move, describing an arc, the knife edge seat 25 being carried downwardly and to the left and the knife edge seat 24 upwardly and to the left. 'I'he movement of the seat 25 as described both carries the knife edge pivot 21 of the freely swingable link 26 downwardly toward the line of action of the springs 34 and causes the right hand end of said link to move upward upon engagement of the underside of link 28 with the adiustable stop pin 31 to carry the line of action of said springs 34 upwardly. Thus, we have a movement of .the line of action of the springs 34 upwardly and of the pivot point of the link 26 downwardly. With the passage of the knife edge seat 25 through the center line of the. springs 34, the swingable link 26 will be snapped upwardly into engagement with the upper stop 36. This moves the center line of the operating springs 34 quickly through the pivot point of the contact lever 28 so that there is no dead center position, bringing the movable contacts 32 into engagement with stationary contacts i8 with a snap.

Upon decrease in pressure, the main operating lever 23 will rotate clockwise moving the knife edge seat 25 upwardly and -to the right and through the line of action of the springs 34 causing the link 26 to pivot within i-ts mounting and carry the line of action of said springs 34 downwardly. Thus we now have a movement of the line of action of the springs downwardly, and of the knife edge seats 25 upwardly. With the passage of -the knife edge seat 25 through the center line of the springs, the link 26 will be moved quickly downwardly moving the center line of the springs 34 quickly through the pivot point of the contact lever 28 to move said lever quickly downward to break the contacts with a snap. The elimination of a dead center position provides an advantage in that while the contacts are in engaged position there is no point -at which the contact pressure is zero but a denite contact pressure is maintained until said contacts are snapped to open position.

It is to be particularly noted at this point that the above described movements of the main operating lever 23 imparts a plurality of movements to the contact lever 28. When the main operating lever 23 is moved in a counter-clockwise direction, it causes the knife edge seats 24 to be moved to the left and upwardly; the movement of the seats 24 to the left carries the contact lever 28 -to the left and into the insulating contact block.'l4 -in a generally horizontal plane, this movement of the operating member eiects snap movement of link 26 to carry the line ofvaction of the springs 34 through seats 24 whereby said contact lever 28 is snapped to cause the contacts -to engage with a snap. With a release in pressure, the main operating lever 23 will move in a clockwise direction under the bias of range spring 38, the link member 26 will rotate and the force exerted by the spring 38 will force the contact lever 28 to move rst in a general horizontal plane to the right and then downwardly with a snap as knife edge seat 25 is carried through the center line of the springs 34. This movement of the contact lever 28 to the right furnishes a dellnite wipe to the contacts and greatly lessens the possibility' of sticking. As a precaution, however, in case a situation arises in which sticking or welding does occur, a hooklike portion 88 is disposed about the knife edge pivots 28 and when the contacts stick is adapted to engage pivots 28 and positively move the contact lever 28 through the pressure of the range spring I38 acting upon thedmain operating lever 23 to thereby break the we The predetermined maximum pressure responsive means or high pressure cutout Il includes a bellows 59 operating upon a toggle lever 4|, said lever il being pivotally supported by a pin liz carried by a supporting bracket 83 which is secured to the base 2| as by studs. A toggle spring 64 is disposed between the end of the pivoted lever Si and an upwardly extending portion 65 of the bracket 63. A second spring SS interconnects a projection 8l on the bracket 63 and a projection 68 on the pivoted lever BI to thereby oppose the movement of the lever 6i by the bellows 59. A stud $9 and a spring holding nut cooperates with said spring 66 to vary the tensionV thereof and thereby the force resisting the action of the bellows 59. In the operation of the high pressure cutout Il, the rise of pressure to a predetermined amount within the bellows 59 overcomes the bias of the spring 66 and the toggle spring 64 so that the toggle formed by the lever 6| and the spring 64 will snap over center to bring a platform like portion 1l provided by the lever 6I into engagement with a projection 12 yextending downwardly from the contact lever 28 to positively move the latter to contacts disengaged position irrespective of the pressure within the main operating bellows.

While certain preferred embodiments of the invention have been specically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilledin the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

What is claimed is:

1. In an electric switch, stationary and movable contacts, a pivoted switching member operable to move -said movable contact, a pivoted supporting member for said switching member, the line through the pivot points cf` the switching member and the supporting member being disposed substantially at right angles to the switching member, means including said pivoted sup-k porting member, a lever member carried by said pivoted supporting member and resilient means interconnecting said switching member and said lever member, to impart a substantially transilatory movement to said switching member when in contacts engaged position to move the movable 3. In an electric switch, a stationary contact', a movable contact, a switching member movable to move said movable contact, and having a knife edge pivotal mounting, a lever member oppositely directed to said switching member and likewise having a knife edge pivotal mounting, spring means interconnecting said switching member to said lever member and means to move the knife edge pivotal mountings so that each describes an arc, said movement of the knife edge pivotal` mountings causing the switching member and the movable contact to move first with a substantially rectilineal movement and then to move rotatively and with a snap action to contacts engaged or contacts disengaged position, and means carried by said pivotal mounting moving means adapted to engage and move said switching member if said contacts should weld during engagement to break said weld and restore normal operation.

4. In an electric switch, a stationary contact, a

pivoted switching member carrying a movable contact to cooperate with said stationary contact,

a lever member, spring means interconnecting said switching member and said lever member, and adapted to move said switching member with a snap action, movable pivotal mountings for said switching member and said lever disposed between the sides of said switching member, means movable to move said pivotal mountings whereby the switching member and the movable contact carried thereon when in contacts engaged position will be moved rst in generally straight line and then rotatively and with a snap action to contacts disengaged position, and hook like means disposed adjacent the switching members pivotal mounting adapted to engage and move said switching member if said contacts should weld during engagement to break said weld and restore normal operation.

5. In an electric switch, a stationary contact,

Y a movable contact, a pivoted switching member movableto move said movable contact, a pivoted lever member, a plurality of spring means interconnecting said -switching member and said lever member and adapted to move said switching member with a snap action, movable pivotal cooperation with said stationary contact, a pivi oted member pivotally supporting said switching member, a lever member p-ivotally supported upon said pivoted supporting member, spring i .means interconnecting said lever member and said switching member and operable upon movement of the pivoted supporting member to move said switching member with a snap action, and pressure responsive means .for actuating said pivoted supporting member, the movement of said pivoted supporting member causing said switching member to move rst generally rectilinearly and then rotatively and with a snap action to contacts engaged or contacts disengaged position, with said movable contact through its being carried by said switching member also moving rst generally rectilinearly and then rotatively and with a snap action to contacts engaged or contacts disengaged position, and means carried by said pivoted supporting member adapted to engage and move said switching member rectilinearly if said contacts should weld during engagement to break said weld with a shearing action and restore normal operation.

mountings for said switching member and said lever member disposed between said spring means, pivotal means movable to move said pivotal `mountings so as to describe an arc, said mover ment of said pivotal mountings causing said switching member and said movable contact to move first substantially rectilinearly and then rotatively to contacts engaged and contacts disengaged position and a pressure responsive means to actuate said pivotal means, and means carried by said pivotal means adjacent the pivotal mountings for said switching member adapted to engage and move said switching member rectilinearly if said contacts should weld during engagement to break said weld with a shearing force and restore normal operation.

6. In an electric switch, a stationary contact. a movable contact, a pivoted supporting member,

oppositely directed knife edge seats thereon, a-

link member carrying knife edge pivots upon the outer edges thereof to cooperate with certain of said knife edge seats, a switching member to move said movable contact and carrying knife edge pivots upon the inner edges thereof to co- .operate with the other of said knife edge seats so'that said switch member is then oppositely directed to said link member, spring means disposed adjacent the knife edge seats interconnecting said switching member and said link member and urging the said knife edge pivots into their respective knife edge seats, means movable to move said pivoted supporting member to cause said knife edge seats to move so that each describes an arc, said movement of said knife edge seats causing said switching member and said movable contact to move rectilinearly and causing said lever member to pivot so as to displace the line of action of said spring means from above said knife edge seats to below to move said switching member and said movable contact with a snap action to contacts engaged or contacts disengaged position and hook like members carried by said supporting member disposed adjacent the knife edge pivots carried by said switching member adapted to engage said switching member if said contacts should weld during engagement to break said weld with a sheari force and restore normal operation.

7. In an electric switch, a stationary contact, a switching member carrying a movable contact for cooperation with said stationary contact, a pivoted member pivotally supporting said switching member, a lever member pivotally supported upon said pivoted supporting member, means for moving said switching member with a snap action including a relatively stationary stop member engageable by the lever member and serving as a fulcrum therefor and spring means interconnecting said lever member and said switching member, and pressure responsive means for actuating said pivoted supporting member, the movement of said pivoted supporting member causing said switching member to move first generally rectilinearly and then rotatively and with a snap action to contacts engaged or contacts disengaged position, with said movable contact by its being carried by said switching member alsa moving rst generally rectilinearly and then rotatively and with a snap action to contacts engaged or contacts disengaged position and means for positively moving said switching member if said contacts should weld during engagement to break said weld and restore normal operation.

8. hi an electric switch, a stationary contact. a switching member carrying a movable contact for cooperation with said stationary contact, a pivoted member pivotally supporting said switching member, a lever member pivotally supported upon said pivoted supporting member, relatively stationary stop means, spring means interconnecting said lever member and said switching member, said spring means and said lever member cooperating to move said switching member with a snap action upon movement of the pivoted supporting member with said lever member being engaged by said stop means to accelerate action of said lever member, the movement of said pivoted supporting member causing said switching member to move rst generally rectilinearly and then rotatively and with a snap action to contacts engaged or contacts disengaged position, with said movable contact by its being carried by said switching member also moving rst generally rectilinearly and then rotatively and with a snap action to contacts engaged or contacts disengaged postion and means for positively moving said switching member .if said contacts should weld during engagement to break said weld and restore normal operation.

9. A switch comprising a movable element, pressure responsive means normally actuating said movable element, a contact arm pivotally supported upon said movable element and movable thereby, means operable under the action of a second pressure responsive means to move said contact arm with a snap action independently of saidmovable supporting element and said first pressure responsive means without moving said movable supporting element, said operable means comprising a supporting member, a toggle link supported at one end thereof, a toggle spring exerting its bias against the free end of said toggle link, with a portion of said toggle link adapted to directly engage said contact arm.

10. A switch comprising a movable element, actuating means therefore, a contact arm pivotally supported upon said movable element and movable thereby, means operable in response to a second actuating means to engage and move said contact arm with a snap action independently of said movable supporting element and said first actuating means without moving said movable supporting element, said operable means comprising a supporting member, a toggle link pivotally supported at one end thereof, a toggle spring biased between the free end of said toggle link and a projecting portion of said supporting member, an adjustable spring means interconnecting said toggle link and said supporting member to oppose the action of said second actuating means, said toggle link being movable to engage said contact arm and move it to disengaged position.

11. In an electric switch, a stationary contact, a movable contact, a pivoted main operating lever, a switching member pivoted on said main lever and carrying said movable contact, the line through the pivots of said switching member and said operating lever being substantially at right angles to the switching member when in contacts engaged position, means including resilient means and the pivoted main lever to effect movement of said switching member and said movable contact first generally parallel to the plane of the stationary contact face and then with a snap action to contacts engaged or contacts disengaged position.

12. In an electric switch, a stationary contact, knife edge seats, pivoted means movable to move said knife edge seats, a link member swingingly mounted in certain of said knife edge seats, a switching member disposed about said link member and carrying a movable contact for cooperation with said stationary contact and pivotally mounted within knife edge seats oppositely directed to said first knife edge seats, a line through the axis of the latter knife edge seats and the pivot of said pivoted means being disposed substantially at right angles to the switching member, spring means disposed adjacent the knife edge seats and interconnecting said switching member and said link member, movement of said knife edge seats by the pivoted means effecting movement of the switching member and the movable Contact carried thereon in a direction generally parallel to the plane of the face of the stationary contact, and effecting movement of the line of action of said spring means through the knife edge seats to move said switching member and the movable contact with a snap action to contacts engaged or contacts disengaged position. l

i3. In an electric switch, stationary and movable contacts, a movable element, pressure responsive means normally actuating said movable element, a switching member pivotally supported upon said movable element and movable thereby to bring about engagement and disengagement of the contacts, means supported by said movable element and actuated thereby to effect snap movement of said switching member, means operable under the action of a second pressure responsive means to move said switching member with a snap action independently of said movable suporting element and said first pressure `responsive means without moving said movable supporting element, said operable means comprising a supporting member, a toggle link supported at one end thereof, and a toggle spring exerting its bias against the free end of said toggle link, said toggle link directly engaging said contact arm to effect movement.

14. A pressure switch comprising stationary and movable contacts, a switching member adapted to move said movablecontact into and out of engagement with said stationary contact, a movable element pivotally supporting the switching member, a pressure responsive actuating means for said movable element, means for inducing snap movement of said switch member comprising a link member supported by said movable element and spring means interconnecting said link member and said switch member, means operable under the action of a second pressure responsive means to move said switch member with a snap action independently of said movable supporting element and said first pressure responsive means, said operable means comprising a supporting member, and a toggle link exerting its bias against the free end of said toggle link, a part on said toggle link being adapted to directly engage said switch member to effect movement thereof.

15. Av pressure switchcomprising stationary means operable in response to a second pressure l responsive means to engage and move said switch member with a snap action independently of said movable supporting element and said rst pressure responsive means, said operable means comprising a supporting member, a toggle link pivotally suported at one end thereof, a toggle spring biased between the free end of said toggle link and a projecting portion of said supporting member, an adjustable spring means interconnecting said toggle link and said supporting member to oppose the action of said second pressure responsive means, said toggle link being movable with a portion thereof `directly engageablewith said switch member to move it to contacts disengaged position.

16. In an electric switch, a stationary contact, a movable contact, a switching member movable to carry said movable contact into and out of engagement with said stationary contact, a pivoted supporting member for said switching member. and means for varying the diierential of operation of the switch comprising a stud, a spring and a nut adjustably supported thereon, a link member interconnecting said spring and `said supporting member whereby the bias of said spring opposes switch closing movement of the supporting member, said nut being engageable by said link in the switch opening movement of the supporting member to effect release of the bias of said spring upon said supporting member during a portion of the movement thereof.

17. In an electric switch, a stationary contact, a movable contact, a switching member operable to move said movable contact, an operating member for said switching member, means for changing the diierential of operation of said switch comprising a stud, a traveling support threaded thereon, a spring supported thereby, a traveling nut carried by said stud, and means to lock said nut in the desired position, and a link secured at one end to said spring and having a lost motion connection at its other end with said operating member whereby the tension of said spring opposes movement of said supporting member in switch closing direction; said nut being engageable by said link to release the tension of said spring uponsaid operating member during a portion of the movement thereof.

18. In an electric switch, a stationary contact, a movable contact, a pivoted main operating `lever, a switching member pivoted thereon and movable to move said movable contact, the line through the pivotsof the switching member and the operating member when in contacts engaged position being substantially at right angles to the switching member, a flipper member pivotally, supported on said operating member, spring means interconnecting said switching member and said flipper member, condition responsive means operable to actuate the main operating lever to move the switching member and the movable contact generally parallel to the plane of the stationary contact face, said movement of the operatingimember also eiecting movement of the pivot of the flipper member through the line of the force of the spring means to move the switching member and the movable contact with a snap action to contacts engaged or disengaged positions.

19.'In an electric switch, a stationary contact, a movable contact, a pivoted main operating lever, a switching member pivotedA thereon and movable to move said movable contact, the line through the pivots of said switching member and said operating member when in contacts engaged position being substantially at right angles to the switching member, a flipper member pivotedly supported upon said operating member, a relatively stationary stop element engageable by said flipper member and serving as a fulcrum therefor, spring means interconnecting said switching member and said fiipper member, condition responsive means operable to actuate said main operating lever to move the switching member and the movable contact generally parallel to the plane of the stationary contact face, said movement of operating member also effecting movement of the pivot of the flipper member or disengaged position. 

